Ozone layer 20 percent thinner over Arctic last winter

The ozone layer over the Arctic thinned out by 20 percent during January this year, a smaller loss than during eight of the last 11 winters, United Nations climate experts said.

"Chemical reactions triggered a 20 percent loss in the ozone layer over the Arctic in January 2006 - a reduction exacerbated by colder stratospheric temperatures during that month," the WMO said in statement.